it was 18 hours, and it ended 4 AM (Eastern), I don't know when the'll replay it (but they probably will). Check the TechTV website, and search for the Call For Help-A-Thon... rerun dates will be on the right hand side of that page...sorry, i don't think I can post links
When you block a person, they can no longer invite you to a private message or post to your profile wall. Replies and comments they make will be collapsed/hidden by default. Finally, you'll never receive email notifications about content they create or likes they designate for your content.
Note: if you proceed, you will no longer be following .